Three years into the mortgage crisis, the public debate over how to stem the unprecedented tide of foreclosures and the damage they are doing to the housing market has largely overshadowed any discussion of the human toll. But researchers have begun to examine what happens to people after they lose their homes and are becoming especially concerned about the harm to children.

The number of children displaced has climbed steadily in recent years, with nearly 40 percent of U.S. school districts surveyed citing foreclosure as the top reason for the surge in homeless students, according to a report this summer by First Focus and the National Association for the Education of Homeless Children and Youth.

Children who are forcibly uprooted from their homes and schools tend to suffer emotionally, socially and academically, studies preceding the mortgage meltdown show. Researchers suspect the same might be happening with children who have been dragged through foreclosures and they are urgently exploring the consequences.

"This foreclosure crisis is the largest forced relocation event we've had in this country since the Great Depression. In the modern educational environment, we've never seen anything come close to this," said Dan Immergluck, a housing policy professor at the Georgia Tech.

Susan Brooking never imagined her family would get tangled up in a mortgage crisis when she and her husband, Robert Brooking Jr., started building a home just north of Charlottesville nine years ago.

But the family's finances collapsed after her husband was laid off from his job working for a home builder in early 2008. In August, the couple received a foreclosure notice and moved out a few weeks later, soon after their 5-year-old son, Connor, began kindergarten.

Susan Brooking settled in at her sister's house with Connor and his 19-month-old brother. Her husband lives nearby with his parents. Neither home was large enough to accommodate the family, but they were able to stay close to Connor's school.

"My son keeps asking why, why, why at every step," Susan Brooking said. Why did they have to move? Why can't he visit his bedroom at the old house? Why are his toys in storage? Why do they have to live apart? Why did he have to leave behind the playground that he and his father had just started building?

"Now he's acting up in class," she said. "All we think about is renting a house in the same school district so we can get some normalcy back into our lives. We don't want to deal with another school and another transition."

Mindy Thiel, a private therapist in Rockville, said she's seen more and more families in the same situation over the past two years. Their kids often express a "feeling of powerlessness," she said. "Even 5-year-olds conceptually get the idea of loss, and they get extremely sad and frustrated that they can't do anything to change the situation."

The longer the foreclosure process drags on, for years in some cases, the more likely children are to lapse into hopelessness and internalize feelings of insecurity that can linger into adulthood, she said.

"They're wondering where their next home, their next school, their next set of friends are going to be," Thiel said. "A poignant issue that's often overlooked is: 'Where will my dog go? What will happen to my fish or my rabbit?' . . . It changes their world view."

About a year into the mortgage crisis, First Focus, a group that advocates for children and families, released a study in May 2008 projecting that 2 million children would lose their homes to foreclosure by 2010. This was a conservative estimate because it was limited to families that defaulted on subprime loans and did not include conventional loans or children evicted from rental units, the group said.

In the District, the Urban Institute found that about one quarter of homes in foreclosure had a public school student living in them in the 2008 school year. The number of public school students affected by foreclosure more than doubled in 2008 from the previous two school years, the study said.

This research, funded by the Open Society Institute, is also looking into foreclosure patterns in New York and Baltimore, examining in part the impact on schools and children. In New York City, the number of students directly affected by forclosure in the 2006 school year rose to 18,525, 59 percent more than the number affected in the 2003 school year, according a study released this fall by the Institute for Education and Social Policy and New York University.

In a study this year of 25 Latino families, many parents reported that foreclosure-related problems strained their relationships with their children and their partners, in part because they often ended up living in cramped quarters with relatives or friends.

Some of the parents in the study, conducted by the National Council of La Raza and the University of North Carolina at Chapel Hill, said their children blamed them for losing the home. Eight families reported increased conflict among siblings. Fourteen parents said their relationships suffered and 10 said they considered leaving their spouses or partners. Two spouses had separated when the interviews took place last year.

Nor is the fallout limited to people who own their homes. About 40 percent of families facing eviction were renters whose landlords were foreclosed upon, according to an estimate by the National Low Income Housing Coalition.

Valeria Jones of Rockville was among the many renters caught unaware when an eviction notice arrived, leaving her family little time to prepare a move.

"Every time I turned around, someone was knocking on the door and talking about foreclosure," Jones said, "and the landlord still kept telling me to ignore it and still kept asking for his rent and threatening that he'd put me out on the street."

Jones said her teenage grandchildren and niece, all of whom live with her, were rattled. They answered doors and read letters and heard the neighbors whisper, she said. "They made themselves crazy with worry."

Then, on moving day in March, Jones was transporting boxes into the family's new rental home when the eviction crew changed the locks on their old home. The kids came home from school to find their belongings in a trash bin.

"They lost the kind of stuff you can't replace, like the journal my granddaughter used to write in all the time and artwork from first grade," Jones said.

The family is uncertain whether they will stay in their new home. It's in a new school district, and she says her granddaughter, a straight-A student, keeps saying, "Grandma, I'll kill myself if you send me to that school."

Under federal law, students who lost their homes to foreclosure can remain in their schools until they find permanent housing even if they moved from their original school districts. If they find a fixed-living arrangement during the academic year, they can stay in their schools until the year ends.

Still, with all the issues the foreclosure crisis raises about the social and emotional development of children and the stability of the schools they are entering and leaving, the issue has not yet attracted the kind of public-policy response it deserves, experts say.

The problem might be the division of labor in government, said Amy Ellen Schwartz, director of New York University's Institute for Education and Social Policy.

"The housing thing is a housing department issue. The education thing is an education department issue," she said. "It's become an 'It's not my turf, it's not your turf' kind of issue, and it's fallen through the cracks a bit."